Electroperforator



Dec. 19, 1944. J w E KE ET AL 2,365,576

ELECTRO-PERFORATOR Filed March 17, 1941 2 Sheets-Sheet l TnJen 01x andMaggy" iforn ey e Dec. 19, 1944. J. w. MEAKER ET AL.

ELECTRO-PERFORATOR z Sheets-Sheet 2 Filed March 17, 1941 Patented Dec.19, 1944 UNITED STATES PATENT OFFIE ELECTROPERFORATOR John W. Meaker,Evans ton, and Edward H. Yonkers, 'Jr., Winnetka, 111.; said Yonkers,Jr..

asslgnor to said Meaker Application March 17, 1941, Serial No. 383,810

2 Claims.

clusively, to an electro-perforator capable of distributing(perforations over an irregular object such as a shoe.

Once! th objects of the invention is to provide an electro-perforator,in which electrical discharges of high voltage are controlled so as toburn clean perforations of the desired diameter through the materialtreated.

Another object of the invention is to provide the apparatus with a handcontrolled device, referred to hereinafter as an applicator, connectedwith the cabinet containing the impulse generating apparatus and itscontrols, by flexible insulated electrical connections, whereby theapplibers, adapted -to contact with opposite sides of the materialtreated, preferably with spring pressure, and said contacting membersbeing formed so that the applicator may be readily moved with respect tothe material and the electrodes kept in proper relation to the materialeven when the material is-not uniform in thickness or has surfaceinequalities.

A more specific object of the invention is to provide anelectro-perforator which may be used for the perforation of leather orlike material. particularly leather or other material made up intoshoes, for. the purpose of ventilating the shoes; and in this connectionthe object of the invention is toprovide a simple and inexpensivedevice, which is easily handled, even by the unskilled, by means ofwhich the electrical discharges may be controlled so as to burn cleanand practically invisible perforations in the shoes, which perforations,however, may be made large enough to be visible if desired. Unlessproperly controlled the electrical discharges are likely'to assume adisruptive character. which j gives material, such as leather, a pebbledor pimpled-appearance usually accompanied byinadequacy in respect to thecleanness and size of the perforations; 3

To make an electrical perforation in the leather of a shoe requires aninside electrode either connected with the source of current orgrounded, as well as an outside electrode. It has been found that to useasan inside electrode a device like a its source.

metal sho tree would require a very large number of different sizes,shapes and kinds to lit the various shoes to be treated, and this wouldinvolve not only selecting the suitable size but connectin it with theelectrical apparatus. This would be a troublesome and time consumingoperation. Another form of inside electrode might be provided by fillingthe shoe with shot or loose chain links or copper sponge. A conductingwire would be attached to any one of these three forms of insideelectrode for the return of or the grounding of the current. These aretroublesome to use for manifest reasons. It is clear that the sparkpenetrating the leather from the outside and entering any one of thesethree, or similar inside electrodes, can travel through this electrodeto any available point of escape, such as a nail in the heel of the shoeor through the sole. Regardless of where the outside electrode maycontact the leather of the shoe, the spark will find its way to thisnail and ultimately by repeated arcing through at this point, may burn ahole through the heel or the sole. The applicator illustrated in thedrawings is tree from these oblections. The outside and insideelectrodes are companion electrodes, always travelling together and witha minimum gapbetween them through which the current jumps. In fact,every inducement is offered the current to pass directly from theoutside to the inside electrode, a distance of perhaps not more than orof an inch. The applicator therefore controls and directs the locationof the spark penetration, and entering the inside electrode, the currentis conducted back to This minimizes the Jumping of the current from theoutside electrode to an adjacent point in the leather which is easier topenetrate and then back inside of the shoe to the inside electrode. Thisalso minimizes the chance of electric shock to the operator since.thecurrent more easily, goe through the channel provided for it and doesnot tend to Jump to any v other route.

connecting ol the one and the installation of an-- other one moresuitable to the shoe being operated upon. The very small spark gapeconomizes in current consumption. The electrical discharges under thecurrent control may burn clean and ,perfect invisible perforations inthe shoe, but

these perforations may be made large enough to be visible if desired.

A further object is to provide for controlling the electrical dischargeswhereby the size of the perforations may be varied.

The ordinary alternating current supply lines operate at 60 cycles persecond which would tend to produce 120 perforations per second which istoo rapid for proper distribution over the irregular surface of a shoeby the manual means contemplated in this invention. Hence, it ispreferred to use direct current interrupted at the proper intervals togive the desired effect, that is, current discharges of sufficientintensity and lasting for a long enough time to produce the actualburning of the material in the formation of the perforations. In placeof the interrupter a condenser and inductance may be used to obtainapproximately, at least, the same eifect. The invention contemplates theuse of a transformer for giving the electrical discharges a highpotential.

The invention is illustrated in certain preferred embodiments in theaccompanying drawings, wherein Fig. l is a view in perspective of theelectroperforator showing the applicator as operating on a shoe, the toeportion of which is indicated in cross-section.

Fig. 2 is a schematic drawing showing the electrical apparatus forgenerating and controlling the perforating discharges.

Fig. 3 is a detailed sectional View of the electrodes of the applicator;and

Fig. 4 is a wiring diagram of an apparatus in which the condenser andinductance take the place of the mechanical interrupter illustrated inFig. 2.

It will be understood that the drawings show forms of the inventionwhich are typical and preferred. The invention, however, is not to beconsidered as limited to these particular forms, the intention being tocover all equivalents and all modifications within the scope of thehereto appended claims.

The apparatus shown in Fig. 2 is shown.as supplied with direct current.The apparatus, however, may be operated from alternating current byinclusion therein of a suitable full wave rectifier.

Referring first to Fig. 1, A is a cabinet containing the apparatus forgenerating and controlling the perforating discharges; and B is theapplicator, comprising a hand grip Hi to which are attached theelectrode supporting members H and i2. The upper electrode member II ispreferably made of insulating material I3 (Fig. 3) encasing theelectrode 14 which terminates within a hollow 15 in the end of themember H, the extremity of which is rounded so a to slide easily overthe leather which latter is indicated at C. The lower electrode memberconsists of a stiff rod 16, the end of which is slotted to receive aflat spring ll to which is attached by screw I8 a conical electrodeelement IS, the upper end of which is preferably rounded so that theapplicator can be moved with respect to the leather of the shoe withease even when there are surface inequalities or when the thickness ofthe material varies. The electrodes are at all times kept in properrelation to the upper and under surfaces of the material by the springaction of the spring member H. The device is thus adapted, for example,to operate on reinforced and thickened portions of the shoe, such as theheel portion and toe portion as well as upon thinner parts.

Referring to Figs. 1 and 3, it will be observed that the upper electrodecomes close to but not into contact with the leather. It is encased in amember composed of some smooth surface insulating material with arounded under surface, the purpose of using an insulating casing being,of course, to protect the operator. The lower electrode comes in directcontact with the leather. This is not essential. The lower electrodemight be made like the upper one. The term electrode member" as used inthe claims is intended to include both an electrode which comes directlyinto contact with the material and one which is carried by or encased inan elementwhich contacts with the material to be perforated.

The letters D indicate the flexible cords or cables containing the wireswhich connect the applicator electrodes with the mechanisms associatedwith the cabinet A. E is the flexible cord which contains the leads fromthe service lines and is preferably provided with a plug 2| adapted forinsertion in an ordinary light socket. For convenience in operation theapplicator is provided with a push button switch 2! for controlling theapplication of the electrical impulses t the material being perforated.This is also a safety feature. With the release of the hand grip thecurrent is cut on.

The apparatus associated with the cabinet A compris s, in addition tothe mechanism contained within the cabinet and to be described later, arotatable button 22 for controlling the volume of current flowingthrough the primary circuit of the transformer; a control button 23 forcontrolling the speed of the make and break motor; a milliammeter 24; amain switch 2!; and a pilot light 26.

Referring now to Fig. 2, the lead 21 contains the main switch 25, thepilot light 28 and the push button switch 2| on the applicator. Thislead is connected with the primary coil 28 0f the transformer F. Thesecondary coil of the transformer is indicated at 29 and the iron coreat 3|. Wire 3| connects the primary coil 28 with one member 32 of theinterrupter, designated G as a whole, the other member 33 of theinterrupter G being connected with the variable resistance 34, themovable contact 35 of which is operated by the button 22 (Fig. 1). Wire36 connects the movable member 35 of the variable resistance with themilliammeter 24, which latter is connected by wire 31 with the othermain lead 33. The motor 39 of the interrupter G is on a shunt circuit llfrom the main leads 21, 38. The interrupter device 42 is shown as ahexagonal cam rotated by the motor 39 and adapted to bear against member32 to cause it to break from member 33. The electrodes ll-IQ ofapplicator B are in circuit 43 with the secondary coil 28 of transformerF. Preferably motor 39 i provided with a device for controlling itsspeed and thereby controlling the number of current interruptions perunit of time, such for example as the variable resistance 40 controlledby the control button 23 (Fig. 1)

Leather and other materials employed in the manufacture of shoes arefairly good dielectrics, that is, non-conductors of electricity. Incarrying out the present invention, sufficient electrical potential isapplied to the electrodes to break through or puncture the material ofthe shoe. It has been found that the size of such perforations isdetermined by the magnitude of the electrical current which is permittedto pass through the holes after the puncture or break down has beenaccomplished by the initial high potential.

In the perforation Of shoe leather it is desirable to employ electricalcurrents in th range of five to fifty milliamperes flowing forapproximately to A of a second; and with currents of this characterthere will ordinarily be no undue distortion of the surface of theleather. Currents of relatively low amperage producing small pores mustbe used with highly finished fine leathers, whereas the larger currentsmay be used on materials with coarser or rougher surfaces. It should beunderstood that in this method of electro-perforation, the current iscaused to flow for a sufllcient time to actually vaporize or burn awaysome of the material. Thi is essential in order to obtain clean andpermanent pores or perforations of sufficient size for effecting thedesired ventilation of the shoe.

It has also been found thatif the electricity is allowed to flow toorapidly through the leatherthat is, too high a current for too short atimethe surface of the leather becomes distorted around each perforationgiving a pimpled appearance which is undesirable. Thus in thesatisfactory electro-perforation of leather shoes, both magnitude andduration of the perforating current must fall within a certain range ofvalues. There are several available means for obtainin electricalimpulses of controlled voltage, current and time characteristics. Itisdeemed preferable to employ the electrical system which is shown inFig. 2. This system consists, it will be seen, from the abovedescription, of a low. voltage source of direct current, at 115 voltsfor example, and a transformer having a primary circuit through whichthe direct current is allowed to pass. The magnitude of this primarycurrent is controlled by the variable resistance 34-35 and is measuredby the meter 24. This primary current energizes the iron core 3|! sothat when the circuit is opened suddenly by means of the interrupter G asingle high voltage impulse is induced in the secondary winding 29. Ithas been found that under average conditions from 10 m 30 impulses persecond can be properly distributed by means of the manual applicator.The potential of the perforating impulses is determined .by the numberof turns of wire in the secondary coil and by the degree ofmagnetization of the iron core at the instant the primary circuit isbroken. The magnetization of the core is determined by the number ofturns in the primary coil and by the magnitude of current which ispermitted to flow therein. In the operation of the apparatus as abovedescribed an excess of potential in no way impairs operation. Hence, itis preferred to provide sufficient turns in the secondary coil so thatan excess of potential is always present to puncture the material of theshoe, at any place where it is desired to make the perforations,regardless of the adjustment of the variable resistance 34-45. Themagnitude and duration of the perforating current also depends upon thedegree of ma netization of the iron core. Thus, since suilicientpotential has been provided, the variable resistance device serves as aneffective control for the amount of current supplied to the primary coilof the transformer, and, consequently, for the size of the perforationsproduced by the electrical impulses. As pointed out above, the pore sizeis determined by themagnitude and duration of the perforating current. a

In certain leathers where the surface is sensitive and the propercurrent setting is consequently too low for a single impulse to producethe desired pore size, the applicator may be passed over the surfacerepeatedly, thereby enlarging the holes to the desired size.

A modified arrangement is indicated in Fig. 4. It is assumed that theleads 44-45 are connected with the secondary coil of a suitabletransformer giving, for example, a potential of 30,000 volts, with theinterposition of a rectifier for converting the alternating current intodirect current. The lead 44 contains a'resistance coil 46 and a sparkgap 41 to prevent leakage of current across the gap between theapplicator electrodes. A line 48 connects the leads 44-45 and isgrounded at 49. It contains an inductance 50 and a condenser 5|. Thisarrangement, which may, of course, be supplied with suitable controls,can be operated to give intermittent discharges of electric currentbetween the electrodes of the applicator of the proper intensity andduration to perforate the material with clean cut perforations; theoperation being as follows: The resistance 46 is selected or adjusted soas to give the number of impulses per second that may be desired. Whenthe condenser is charged to a potential sufflcient to [break down boththe spark gap 41 and the material in the gap at the applicator, currentwill flow through the system at an intensity and for a period of timedepending upon the capacity of the condenser 5| and the inductance ofthe coil 50. The action of the inductance 50 and the condenser 5| makesthe current oscillatory and prevents a too rapid discharge.

We claim:

1. In an electro-perforator, a manually operated applicator providedwith a pair of electrode members adapted to contact under springpressure with opposite sides of the material to be perforated, one ofsaid members comprising an electrode and an insulated sheathing having arecess at its extremity to the bottom of which the electrode extendswithout contact with the material operated upon.

2. In an electro-perforator, a manuall operated applicator provided withan upper electrode having a sheathing of insulating material formed witha rounded extremity, and a lower electrode comprising a flat spring anda conical electrode element on said spring in line with the end of theupper electrode.

JOHN W. MEAKER. EDWARD H. YONKERS, JR.

